How to choose the self-locking tuning screw suitable for precision printing equipment?
Choosing self-locking tuning screws suitable for precision printing equipment needs to be screened one by one around the four dimensions of core working conditions, precision requirements, installation space and environmental adaptability of printing equipment, and combined with the functional requirements of components. The following are systematic selection steps and key points:
Clarify the accuracy and adjustment requirements of the adaptive parts.
Different printing parts have significant differences in the accuracy requirements of screws, so priority should be given to matching:
Positioning of printing plate cylinder and impression cylinder: Micro-adjustment accuracy (0.01–0.05 mm) is required, and gradual pitch, radial grooving or multi-segment staggered thread structure are preferred to eliminate thread clearance, ensure the parallelism and clearance of the cylinder to be uniform, and avoid overprint deviation.
Adjustment of anilox roller and scraper seat: both angle/pressure adjustment accuracy and vibration resistance should be considered. Self-locking structure with butterfly-shaped elastic sheet and coaxial locking ring is recommended to prevent uneven ink layer caused by scraper displacement during high-speed operation.
Gap adjustment of ink roller: the accuracy requirement is slightly lower (±0.1mm), and asymmetric tooth-type self-locking screws can be selected, giving consideration to adjustment efficiency and locking performance.
Match the vibration condition and anti-loosening grade of the equipment.
High-speed operation (10,000+prints/hour) and frequent start-stop of precision printing press will produce continuous vibration, so it is necessary to pay attention to the locking reliability of self-locking structure:
Strong vibration parts (roller driving side, high-speed ink roller): radial grooving+pre-tensioned elastic sheet or asymmetric tooth design is preferred. This kind of structure generates large friction force through radial extrusion of screw pair, and its anti-loosening performance is better than that of design relying solely on spring washer, and no additional reinforcement is needed.
Medium and low vibration parts (stamping platform, side plate positioning): simple self-locking structure with locking ring can be selected, giving consideration to cost and practicality.
Note: it is necessary to confirm the anti-vibration test grade of the screw (if it meets the ISO 16130 standard) to avoid loosening in long-term use.
Adapt to installation space and structural constraints
The space of ink path and wall plate in precision printing machine is small, so compactness should be given priority:
Narrow space (such as the inner side of roller bearing seat and scraper arm): choose countersunk head/thin head design, and cooperate with integrated structure without additional locking parts to reduce installation volume; The head interface is preferably selected as inner plum blossom/inner hexagon, which is suitable for tool operation in narrow space.
Parts that need to be prevented from rotating (such as scraper seat fixing): the design with flange edge and anti-rotation tooth pattern is selected. The flange can increase the contact area, and the tooth pattern can prevent the screw from rotating and improve the connection stability.
Meet the requirements of environmental corrosion resistance and wear resistance.
Printing equipment is exposed to ink, cleaning agent and humid air for a long time, and screws should have excellent corrosion resistance and wear resistance;
Material selection: 316 stainless steel (acid and alkali resistance, ink corrosion resistance) or titanium alloy (lightweight+high strength) is preferred; If higher wear resistance is needed, carbon steel can be plated with hard chromium/dacromet treatment, and the surface hardness can reach more than HV800, thus prolonging the service life.
Protection grade: For the parts in contact with ink dust or wet environment (such as ink path system), choose screws with sealing flanges, and the protection grade should reach IP65/IP67 to prevent foreign objects from entering the thread pair and causing jamming.
Give consideration to installation and debugging efficiency and maintenance cost.
Debugging convenience: choose screws with unified operation interface (such as plum blossom groove in the whole system) to facilitate the universal use of tools; Part of the design with scale marks can realize rapid repeated positioning and shorten the debugging time of plate changing.
Maintainability: give priority to the structure that can be disassembled repeatedly and has small attenuation of self-locking performance to avoid locking failure after repeated maintenance; At the same time, confirm the universality of spare parts and reduce the inventory cost.
Refer to the original specifications and industry standards of equipment.
For imported printing machines such as Heidelberg, Roland and Komori, the recommended model of the original factory or the substitute brand that meets its technical specifications is preferred to avoid equipment failure due to mismatched specifications.
If the equipment is made in China, it should be selected according to GB/T 3098.20 (self-locking fastener standard) or ISO 10664 (precision thread standard) to ensure the performance compliance.
